The present invention relates generally to mechanical punching apparatuses for copper smelting converters. More particularly the invention relates to a mechanical punching apparatus which can accurately and effectively punch the tuyere of a converter whose position changes with the rotating motion of the converter.
A matte containing 50 to 60% copper which has been smelting in a copper smelting process is converted into blister copper containing about 98% copper in a converting process. The converter used in the converting process is called a Pierce-Smith Type converter which is substantially cylindrical and is disposed so that its longitudinal axis is horizontal. The converter has tuyeres on the lower part of its side wall. More specifically, a plurality of tuyeres are arranged in a line parallel to the longitudinal axis of the converter. Usually, the diameter of each tuyere is about 4 to 5 cm, and about fifty tuyeres are provided at interval of about 15 cm. Compressed air under a pressure of about 1.3 kg/cm.sup.2 is supplied through the tuyeres directly to the molten matte in the converter for causing an oxidation reaction of the matte. Accordingly, in the converting process the molten matte is adiabatically cooled by the blowing air at the ends of the tuyeres, as a result of which the matte is liable to solidify and become encrusted at the ends of the tuyeres. Alternatively, slag formed in the process, which may be a composite oxide containing FeO, SiO.sub.2, Fe.sub.3 O.sub.4, etc., is liable to solidify and become encrusted at the ends of the tuyeres. If such solidified encrustations form, which tend to clog the tuyeres, the compressed air cannot be supplied in sufficient quantities to the converter. In such an event, it is necessary to insert punching rods into the encrusted tuyeres to clear the tuyeres.
On the other hand, as the oxidation reaction advances in the converter and accordingly the level of the molten matte is decreased in the converter, it is necessary to rotate the converter to change the position of the tuyeres so that the compressed air is supplied into the deeper portion of the molten matte in the converter so that the oxidation reaction can be completely carried out in the converter.
As the converter is rotated, the horizontal direction, the vertical direction and the inclination angle of each tuyere are changed. Accordingly, it is necessary to move the mechanical punching apparatus as the position of the tuyere is changed. A conventional mechanical punching apparatus, for instance, as disclosed in Japanese Published Patent Application No. 6684/1971, has three separate mechanisms for regulating the horizontal direction, the vertical direction and the inclination angle, respectively. The conventional mechanical punching apparatus is positioned by operating each of the three mechanisms whenever the converter is rotated. This operation is troublesome and requires particular skill. Moreover, a mechanical punching apparatus exerts great impact when punch the tuyeres. Therefore, the apparatus itself and the punching rod have a tendency to wear. Accordingly, it is necessary to inspect and repair them. However, since the conventional mechanical punching apparatus has an intricate construction, its overhaul and maintenance are considerably difficult.